Egle Sendzikiene

Technological assumptions for biogas purification

Biogas can be used in the engines of transport vehicles and blended into natural gas networks, but it also requires the removal of carbon dioxide, hydrogen sulphide, and moisture. Biogas purification process flow diagrams have been developed for a process enabling the use of a dolomite suspension, as well as for solutions obtained by the filtration of the suspension, to obtain biogas free of hydrogen sulphide and with a carbon dioxide content that does not exceed 2%. The cost of biogas purification was evaluated on the basis of data on biogas production capacity and biogas production cost obtained from local water treatment facilities. It has been found that, with the use of dolomite suspension, the cost of biogas purification is approximately six times lower than that in the case of using a chemical sorbent such as monoethanolamine. The results showed travelling costs using biogas purified by dolomite suspension are nearly 1.5 time lower than travelling costs using gasoline and slightly lower than travelling costs using mineral diesel fuel.

Optimisation of enzymatic transesterification of linseed oil and pork lard mixture with ethanol using response surface methodology

Transesterification of linseed oil and pork lard mixture with ethanol was studied by applying a biotechnological method. The effectiveness of 16 lipases was evaluated, and the most effective lipase, Lipolase 100u2009L (EX), was selected for reaction condition optimisation by response surface methodology based on a Box-Behnken design. The influence of the main process parameters was evaluated, including the reaction temperature, ethanol to triglyceride molar ratio, lipase amount, and reaction time on transesterification yield. The optimal reaction conditions were found as follows: reaction temperature of 32.79u2009°C, ethanol to oil molar ratio of 5.99, lipase concentration of 6.39%, and reaction time of 7.95u2009h, with an expected transesterification yield of 52.2%. Optimised enzymatic pork fat and linseed oil mixture transesterification with ethanol was less effective compared with the chemical transesterifications described elsewhere; therefore, the step-wise transesterification procedure should be applied by addi...

Enzymatic microalgae oil transesterification with ethanol in mineral diesel fuel media

This article examines opportunities of enzyme application during the production of biodiesel from microalgae oil by its transesterification in the mixture with mineral diesel fuel. The oil and mineral diesel fuel ratio in the reaction mixture enabled a yield of 7% ester content in the mixture. Effectiveness tests were conducted on seven industrial lipases, and Lipozyme TL IM was selected as the most effective lipase for further optimization. The process of algae oil transesterification with ethanol was optimized by applying response surface methodology. The interactions and impacts of the following independent variables on the transesterification yield were evaluated: ethanol and oil molar ratio, process duration, lipase content, and temperature. Optimum conditions were determined: a temperature of 30u2009°C, 13.26% biocatalyst (from the oil content), an ethanol and oil molar ratio of 4.54:1, and a process duration of 13u2009h. The transesterification yield of the product under the above conditions reached 98%.